Data Propagation How fast does information move in the network?

Below we present the witnessed propagation behaviour in the
network. It is measured by connecting to a large random sample of
nodes in the network and watching for inv-messages that
indicate that a node has received a block/transaction, has verified
its validity and the node will provide it upon request. It is based
on the findings
by Decker
and Wattenhofer (2013) using a modified client to collect the data
and take daily snapshots. The plots and metadata are re-evaluated on a
daily basis and are archived for later reference and measure the
impact of networking changes.

Block propagation

A block at its core is a set of transactions that the block
creator believes to be valid. As such blocks may reach considerable
size, compared to individual transactions. Currently capped at 1MB in
size by convention among the nodes, the size would grow quickly as
adoption of Bitcoin picks up. A larger block size would also mean that
the broadcast slows down considerably, increasing the probability of
finding a block while another block is already being propagated.

Block Percentiles

50th

6.496 seconds

75th

15.068 seconds

90th

51.835 seconds

95th

130.586 seconds

99th

426.271 seconds

Transaction propagation

Slow propagation of transactions may increase the chances of a successful double-spending attack.